We know him from the “Fallout” video game series. Here, each car is powered by a nuclear fission engine, which regularly results in devastating explosions and lots of radiation during the course of the game.
It is therefore not surprising that radioisotope thermoelectric generators (RTGs) are only used far from populated areas, more specifically on missions to the outer planets. Indeed, plutonium 238 is a powerful alpha emitter with a half-life of just under 90 years.
This would be a particularly deadly element, especially in the event of direct contact, that is to say in the food chain. It could also be used to create a chain reaction, that is, ultimately to build a nuclear bomb.
Fortunately, alpha radiation can be blocked with little effort, so Pu-238 can be used practically. Leaving our planet for this is probably not a bad idea.
A plutonium battery converts the emitted energy into energy in the form of infrared light. These RTGs were previously quite heavy and could only provide a few watts of electricity. The reason for this is simple: it is undesirable to combine too much Pu-238, as this could trigger unpredictable and uncontrollable nuclear fission processes.
NASA therefore tried to increase efficiency with a predefined limit, which was remarkably successful in early studies. The new battery can produce 8 watts of electricity from just over 100 grams of Pu-238, stable for decades. It only takes an area of a little less than 30 by 30 centimeters (one foot by one foot) to emit infrared light.
The second phase of research should make it possible to make further improvements. Currently, the plutonium battery is almost five times more efficient than its predecessors. Through the use of improved materials it should be possible to increase it further by the same factor.
Above all, this would make it possible to further reduce the size of the structure, in order to build satellites as small and light as possible, which must do without sunlight. The power supply for electronics and additional measuring instruments would still be ensured over a very long period.
Although the performance of such a battery should be absolutely impressive, there is always a risk that the satellite, power Source and Pu-238 will fall directly back onto the earth’s surface. And if it happens, it should be in the smallest doses possible, which would otherwise be better near Saturn, Neptune or in the Oort cloud.
